Brawn GP Formula One driver Jenson Button of Britain watches a monitor in the team garage during the first practice session for the Chinese Grand Prix in Shanghai yesterday.

PHOTO: AP

Jenson Button made the best possible start to his quest for a third successive Formula One victory by setting the quickest lap time in yesterday’s two practice sessions for the Chinese Grand Prix.

The Briton, who won the first two races of the season from pole position, again showed the pace of his Brawn GP car with a storming lap of 1 minute, 35.679 seconds late in the second session.

“We’ve improved the car a lot over the day, but there’s still a bit more work to do until I’m completely happy,” said the 29-year-old, who leads the championship by five points from teammate Rubens Barrichello. “There seemed to be a lot of traffic on the track today [Friday], so my main concern was finding some clear air.”

German Nico Rosberg also left it late before posting a time of 1 minute, 35.704 seconds for Williams to edge Brazilian Barrichello (1 minute, 35.881 seconds) and deny Brawn GP the top two times of the day.

“The major thing for us at the moment is that this season we have consistency from one track to another,” said Rosberg, who has looked quick in practice but had disappointing race results so far this season. “We’re now going to a race and not getting any big surprises as we seem to have learned from our mistakes from last year.”

The Brawns were expected to dominate the weekend after their rear diffuser was declared legal on Wednesday, but the Red Bulls of Mark Webber and Sebastian Vettel — fourth and fifth quickest — showed it was possible to go fast without one.

“We had perfect driving conditions today so we’ll see how we go tomorrow. I enjoyed it out there,” Australian Webber said.

World champion Lewis Hamilton had put his McLaren team’s troubles behind him by setting the quickest time in first practice, but faded in the second session.

The 24-year-old Briton, whose title defense has been marred by struggles on the track and controversy off it, finished 13th fastest in the quicker afternoon session at the track where he claimed his last win in the penultimate race of last season.

“The team have worked very hard, but we’ve still got a long way to go,” Hamilton said.

Ferrari’s travails also continued, with Brazilian Felipe Massa 12th fastest in second practice and Kimi Raikkonen managing only the 14th best time for the reigning constructors’ champions.

Raikkonen came off the track in both sessions, one of several drivers struggling with grip as the teams weighed their tire choices for the race tomorrow.

“The point is we are too slow compared to the teams currently at the top of the order,” the Finnish 2007 world champion said. “We must try and improve the car, at the moment we are not able to fight for the title.”